// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "ui/views/background.h"

#include "base/logging.h"
#include "base/macros.h"
#include "build/build_config.h"
#include "ui/gfx/canvas.h"
#include "ui/gfx/color_utils.h"
#include "ui/views/painter.h"
#include "ui/views/view.h"

#if defined(OS_WIN)
#include "skia/ext/skia_utils_win.h"
#endif

namespace views {

// SolidBackground is a trivial Background implementation that fills the
// background in a solid color.
class SolidBackground : public Background {
public:
    explicit SolidBackground(SkColor color)
    {
        SetNativeControlColor(color);
    }

    void Paint(gfx::Canvas* canvas, View* view) const override
    {
        // Fill the background. Note that we don't constrain to the bounds as
        // canvas is already clipped for us.
        canvas->DrawColor(get_color());
    }

private:
    DISALLOW_COPY_AND_ASSIGN(SolidBackground);
};

class BackgroundPainter : public Background {
public:
    BackgroundPainter(bool owns_painter, Painter* painter)
        : owns_painter_(owns_painter)
        , painter_(painter)
    {
        DCHECK(painter);
    }

    ~BackgroundPainter() override
    {
        if (owns_painter_)
            delete painter_;
    }

    void Paint(gfx::Canvas* canvas, View* view) const override
    {
        Painter::PaintPainterAt(canvas, painter_, view->GetLocalBounds());
    }

private:
    bool owns_painter_;
    Painter* painter_;

    DISALLOW_COPY_AND_ASSIGN(BackgroundPainter);
};

Background::Background()
    : color_(SK_ColorWHITE)
#if defined(OS_WIN)
    , native_control_brush_(NULL)
#endif
{
}

Background::~Background()
{
#if defined(OS_WIN)
    DeleteObject(native_control_brush_);
#endif
}

void Background::SetNativeControlColor(SkColor color)
{
    color_ = color;
#if defined(OS_WIN)
    DeleteObject(native_control_brush_);
    native_control_brush_ = NULL;
#endif
}

#if defined(OS_WIN)
HBRUSH Background::GetNativeControlBrush() const
{
    if (!native_control_brush_)
        native_control_brush_ = CreateSolidBrush(skia::SkColorToCOLORREF(color_));
    return native_control_brush_;
}
#endif

// static
Background* Background::CreateSolidBackground(SkColor color)
{
    return new SolidBackground(color);
}

// static
Background* Background::CreateStandardPanelBackground()
{
    // TODO(beng): Should be in NativeTheme.
    return CreateSolidBackground(SK_ColorWHITE);
}

// static
Background* Background::CreateVerticalGradientBackground(SkColor color1,
    SkColor color2)
{
    Background* background = CreateBackgroundPainter(
        true, Painter::CreateVerticalGradient(color1, color2));
    background->SetNativeControlColor(
        color_utils::AlphaBlend(color1, color2, 128));

    return background;
}

// static
Background* Background::CreateVerticalMultiColorGradientBackground(
    SkColor* colors,
    SkScalar* pos,
    size_t count)
{
    Background* background = CreateBackgroundPainter(
        true, Painter::CreateVerticalMultiColorGradient(colors, pos, count));
    background->SetNativeControlColor(
        color_utils::AlphaBlend(colors[0], colors[count - 1], 128));

    return background;
}

// static
Background* Background::CreateBackgroundPainter(bool owns_painter,
    Painter* painter)
{
    return new BackgroundPainter(owns_painter, painter);
}

} // namespace views
